2017 day 13 Complete!

2017/day13/day13.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+)
+
+var lyrs map[int]int
+
+func main() {
+	inp := StdinToStrings()
+	lyrs = make(map[int]int)
+	for i := range inp {
+		pts := strings.Split(inp[i], ":")
+		lyrs[Atoi(pts[0])] = Atoi(strings.TrimSpace(pts[1]))
+	}
+	fmt.Println("== Part 1 ==")
+	fmt.Println("Total Severity:", HitchARide(0, false))
+
+	fmt.Println("== Part 2 ==")
+	fmt.Println("Delay", FindNoSeverity(), "picoseconds")
+}
+
+func HitchARide(delay int, brk bool) int {
+	var tm, top, sev int
+	for k := range lyrs {
+		if k > top {
+			top = k
+		}
+	}
+	for tm = delay; tm <= (top + delay); tm++ {
+		if v, ok := lyrs[(tm - delay)]; ok {
+			// There is a scanner here, did it see us?
+			if FindPos2(tm, v) == 0 {
+				sev += (tm * v)
+				if brk {
+					return -1
+				}
+			}
+		}
+	}
+	return sev
+}
+
+func FindNoSeverity() int {
+	maxInt := int((^uint(0) >> 1))
+	for i := 0; i < maxInt; i++ {
+		if HitchARide(i, true) == 0 {
+			return i
+		}
+	}
+	return -1
+}
+
+func FindPos(tm, lngth int) int {
+	var ret int
+	var isAsc bool
+	for i := tm; i > 0; i-- {
+		if ret == lngth-1 || ret == 0 {
+			isAsc = !isAsc
+		}
+		if isAsc {
+			ret++
+		} else {
+			ret--
+		}
+	}
+	return ret
+}
+
+func FindPos2(tm, lngth int) int {
+	loop := (lngth - 1) * 2
+	pos := (lngth - 1) - int(math.Abs(float64((lngth-1)-(tm%loop))))
+	return pos
+}
+
+func StdinToStrings() []string {
+	var input []string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = append(input, scanner.Text())
+	}
+	return input
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi")
+	}
+	return ret
+}

2017/day13/input

@@ -0,0 +1,44 @@
+0: 3
+1: 2
+2: 5
+4: 4
+6: 4
+8: 6
+10: 6
+12: 6
+14: 8
+16: 6
+18: 8
+20: 8
+22: 8
+24: 12
+26: 8
+28: 12
+30: 8
+32: 12
+34: 12
+36: 14
+38: 10
+40: 12
+42: 14
+44: 10
+46: 14
+48: 12
+50: 14
+52: 12
+54: 9
+56: 14
+58: 12
+60: 12
+64: 14
+66: 12
+70: 14
+76: 20
+78: 17
+80: 14
+84: 14
+86: 14
+88: 18
+90: 20
+92: 14
+98: 18

2017/day13/testinput

@@ -0,0 +1,4 @@
+0: 3
+1: 2
+4: 4
+6: 4